1. Field of the Invention
The present invention relates to a shell assembly for winding tire cord strip which is used in manufacturing tires for automobiles or belt cord strip which is used in manufacturing industrial belts, such as V-belts, conveyor belts, etc.
2. Description of the Prior Art
Since tires for automobiles can bear air pressure and absorb any impact, the frame portions of the tires are provided with cord strip formed of fabrics, such as rayon, nylon, polyester, etc., coated with rubbers of good quality, which is folded over and over again to form outer wall structures. For manufacturing industrial belts, provided is cord strip formed of fabrics, such as rayon, nylon, etc., coated with rubbers of good quality, which is folded over and over again so as to increase tension and durability.
Accordingly, in manufacturing the tires or the belts, cord strip, which is material for the tires or the belts, is prepared first of all. Since the cord strip is wound on a shell assembly for winding the cord strip, the shell assembly must provide solidity and elasticity as compared to a shell assembly for winding the usual fabrics. Furthermore, it is required that the shaft member is strong and the square holes at both sides of the shell assembly are arranged in a straight line with each other.
To this end, the conventional shell assembly is made of cylindrical solid wood with square hole for a shaft formed at the center thereof.
However, since the shell assembly is made of a natural wood, a large number of process are required along with special treatment from selection of the material to manufacturing the material, resulting in increase of the costs. Also, since the shell assembly is made of a natural wood, it is very heavy and transformed depending on the change of the external environment, and therefore the uniformity of the quality is not guaranteed.
In order to overcome these drawbacks, the applicant of the present application has developed an improved shell assembly for winding tire cord strip or belt cord strip, which is disclosed by Korean Patent No. 351,176.
According to the aforesaid patent, the shell assembly for winding tire cord strip or belt cord strip comprises: a cylindrical pipe member made of metal or plastic; a core body including a square pipe made of metal, a tapered square pipe body formed with reinforcing ribs at the edges thereof on both sides of the square pipe, and flanges attached to the ends of the tapered square pipe body, said cylindrical pipe member and said core body constituting a shaft member; and a paper layer formed on the surface of the pipe member at a fixed thickness, so that solidity and durability of the shell assembly can be obtained.
The shell assembly as mentioned above is of good quality; however, the cost required for manufacturing the shell assembly becomes high, and the weight itself may be over 40 Kg due to formation of thick paper layers, so that it may not be convenient to handle the shell assembly.